ABSTRACT
If WI(P) < 1, system tranter coefficient W (P)is increasing; if WI(DP) 1, that W(P) ; if WI(P) > 1, denominator of (4.22) will negative and our system will be in selfexcitation mode.
The stability condition of a system is defaulted because the separate components of the left part of an inequality (under the mentioned above conditions) already are more than 1. Physically it means that even the very small own asymmetrical operating current of thyristors is memorizing in an iron core of the transformer; reverting to a control circuit of thyristors in the next halfcycie; summarizing with operation current; amplifying an asymmetry of currents in control circuit of thyristors; and so on to complete saturation of the transformer core, Fig. 4.13.
